Musk thistle is an herbaceous, biennial plant that grows to 6 ft. (1.8 m) tall. It has become a serious invader of open lands throughout the continental United States. It can be recognized by its showy, red-purple flowers and very spiny stem and leaves. Flowering occurs from June to September. The large, disk-shaped, terminal flower heads droop when mature. Musk thistle invades a variety of disturbed areas. Pastures are particularly at risk because musk thistle is unpalatable to livestock. Once established it can spread rapidly due to high seed production (as much as 120,000 seed per plant). Musk thistle is native to Western Europe and was accidentally introduced into the United States in the early 1900s.

Infestation; A pile of fill dirt left over winter. The following spring, the pile was covered in musk thistles. Kris Johnson, Great Smoky Mountains National Park, Bugwood.orgAdditional Resolutions & Image Usage

EDDMapS Distribution:This map is incomplete and is based only on current site and county level
reports made by experts and records obtained from USDA Plants Database.
For more information, visit www.eddmaps.org

State(s) Where Reported invasive.Based on state level agency and organization lists of invasive plants from WeedUS database.